This application claims priority from Japanese Patent Application No. 2001-213761 filed on Jul. 13, 2001, and No. 2002-28750 filed on Feb. 5, 2002, the disclosures of which are hereby incorporated by reference herein.
The present invention relates to a rendering process for displaying three-dimensional images on a two-dimensional screen, such as on a television monitor, a device used therefor, a recording medium having recorded thereon a rendering process program and such rendering process program.
There are accelerating trends in higher integration and faster processing speed of processors and memories in recent television game console machines and personal computers, so that a rendering processing device composed of such game console machine or personal computer can generate fine, high-definition, diversified two-dimensional images with real presence in a real-time manner, and can display them on two-dimensional monitor screens.
When a three-dimensional image is rendered on a two-dimensional monitor screen, the three-dimensional polygon data are subjected to various geometric processes such as coordinate conversion, clipping and lighting, and the resultant data are further subjected to transparent projection conversion. The rendering processing device pastes textures having various colors and patterns onto polygons to thereby give desired colors and patterns to the objects. Such pasting of textures onto polygons is generally referred to as texture mapping.
In texture mapping, the rendering processing device first sets texture coordinate values corresponding to the apexes of a polygon, and generates texel coordinate values corresponding to the individual pixels within the polygon by a linear interpolation operation, referred to as a so-called DDA (digital differential analysis). From the texel coordinate values, the rendering processing device then determines address values used for making reference to texel colors, based on which texel colors of the texture stored in a texture buffer are referred to. The rendering processing device then pastes the referenced texel colors to the individual pixels within the polygon to thereby complete the texture mapping.
As described in the above, the conventional rendering processing device generates the texel coordinate values (i.e., texel color reference addresses) based on the individual apexes of the polygon, so that the individual texel coordinate values within the polygon cannot directly be adjusted.
The present invention was proposed to address the foregoing problems, and an object thereof resides in providing a rendering process capable of adjusting the individual texel coordinate values on the surface of a polygon, that is, moving patterns or the like on the surface of a polygon without moving such polygon per se, a device used therefor, a recording medium having recorded thereon a rendering process program and such rendering process program.
In the present invention, a shift value for shifting a texel coordinate value generated from apex coordinate values of a polygon is acquired, and such shift value is then used for correcting the texel coordinate value generated from the apex coordinate values of the polygon. The corrected texel coordinate value is then used for obtaining color information from a texture table in which the individual pixels express at least color information, and the color information is assigned to the polygon.
In other words, the present invention allows the individual texel values to be adjusted respectively by correcting the texel coordinate value generated from the apex coordinate values of the polygon using the shift value. The present invention also allows patterns or the like within the polygon to be altered or moved without moving such polygon per se (i.e., without altering the apex coordinate values of the polygon) by acquiring color information from a general texture table based on such corrected texel coordinate value.
Other and further objects and features of the present invention will become obvious upon an understanding of the illustrative embodiments about to be described in connection with the accompanying drawings or will be indicated in the appended claims, and various advantages not referred to herein will occur to one skilled in the art upon employing of the invention in practice.